Help. Java run time error

I keep getting this java error and don't know what it means or how to resolve it. Program compiles with javac xxxxxxxxx.java but generates the following error with java xxxxxxxxxxx

D:\Documents and Settings\Desktop\MyJava>java SecureWebServer
Exception in thread "main" java.lang.NoClassDefFoundError: SecureWebServe
Caused by: java.lang.ClassNotFoundException: SecureWebServer
at java.net.URLClassLoader$1.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
Could not find the main class: SecureWebServer. Program will exit.